Updated at 2:20p.m. ET: In a hearing marked by sometimes sharp and pointed exchanges, Secretary of State Hillary Clinton told the Senate Foreign Relations Committee she took responsibility for not adequately protecting U.S. personnel in the Sept. 11 attack on a diplomatic facility in Benghazi, Libya that resulted in the killing of Ambassador Chris Stevens and three other Americans.

While being grilled by Sen. Ron Johnson, R-Wis., a fired-up Hillary Clinton defends her department's handling of the flow of information concerning the cause of the deadly attack on the US consulate in Benghazi on Sept. 11th, 2012, maintaining accusations of misleading Americans could not "be further from the truth."

Defending the administration’s immediate handling of the attack, Clinton clashed at times with Republicans over the account the administration gave in the initial days after Sept. 11.

Clinton said the Obama administration did not try to mislead the American people about the cause of the attacks. “Nothing could be further from the truth,” she said as she sparred with Sen. Ron Johnson, R- Wisc.

She angrily told Johnson that at this stage it did not really matter what the precise origins or motives of the attack were: “What difference at this point does it make?”

She told Arizona Sen. Jeff Flake, a Republican, “we did not have a clear picture” of all that was going on in Benghazi although she did acknowledge that senators had “legitimate questions” about the administration’s account.

Sen. John McCain, R- Ariz., -- after telling Clinton “we are proud of you” and that all over the world “you are viewed with admiration and respect” -- delivered a blistering criticism of the Obama administration’s handling of the events in Libya.

“There are many questions that are unanswered and the answers you’ve given this morning are frankly not satisfactory to me,” McCain told Clinton. He added “the American people and the families of these four brave Americans still haven’t gotten the answers they deserve.”

He asked Clinton whether she was aware of numerous warnings from Stevens and other Americans in Libya that the facility in Benghazi was not capable of resisting a sustained assault. He also said there had been other warning signs such as an attack on the British ambassador to Libya.

He angrily asked Clinton why Defense Department forces were not nearby to defend the Benghazi facility.

Last month a report issued by the Accountability Review Board (ARB) appointed by Clinton, blamed State Department officials for “systemic failures and leadership and management deficiencies” that led to protection for the Benghazi facility that was “grossly inadequate to deal with the attack that took place.”

In her response to McCain, Clinton said, as she did to other senators on the panel, that some additional information on the causes and circumstances of the attack is in the classified portions of the report issued by the ARB. Senators and Senate staff can read the classified portions of the ARB report, but the public cannot.

Sen. John McCain, R-Ariz., grills Secretary of State Hillary Clinton on the administration's handling of the attack on the US consulate in Benghazi and the events that followed.

And she blamed members of Congress for holding up additional aid to Libya that might make the country more secure and less chaotic.

Clinton was testifying Wednesday afternoon on Benghazi before the House Foreign Affairs Committee.

In his questioning of Clinton Wednesday morning, Sen. Rand Paul, R- Ky., told her, “I’m glad that you’re accepting responsibility. I think that ultimately with your leaving, you accept the culpability for the worst tragedy since 9/11, and I really mean that. Had I been president at the time and I found that you did not read the cables from Benghazi, you did not read the cables from Ambassador Stevens, I would have relieved you of your post.”

He added, “It’s a failure of leadership” which cost the Americans in Benghazi their lives. “I think it’s good that you’re accepting responsibility-- because no one else is.”

Paul also argued that U.S. personnel ought to never have been sent to Benghazi “in a war zone” without a military guard. “You shouldn’t send them in with the same kind of embassy staff that you have in Paris,” he added.

While testifying before the Senate Foreign Relations Committee about the murders of U.S. diplomatic personnel in Benghazi, Libya, Secretary of State Hillary Clinton got emotional as she recalled the flag-draped coffins at Andrews Air force Base in the days following the attack, stating her work is "not just a matter of policy; it's personal."

Clinton replied that all four State Department officials criticized in the ARB report for their roles on the Benghazi events had been removed from their jobs and placed on administrative leave. “The ARB (report) made very clear that the level of responsibility for the failures that they outlined was set at the assistant secretary level and below.”

The furor over the Benghazi attack helped derail one possible nominee to replace Clinton at the State Department, UN ambassador Susan Rice, whom Republicans assailed for using administration talking points that portrayed the incident as a spontaneous response to an inflammatory anti-Islamic video.

But Clinton told the committee that in the hours and days after the attack, “I was not focused on talking points” and “I wasn’t involved in the talking points process.”

In her opening statement, Clinton told the committee, “As I have said many times since September 11, I take responsibility. Nobody is more committed to getting this right. I am determined to leave the State Department and our country safer, stronger, and more secure.”

Clinton's voice choked with emotion as she recalled the return of “those flag-draped caskets” from the Americans killed in Benghazi and put her arms “around the mothers and fathers, sisters and brothers, sons and daughters” of those killed.

Clinton also used her testimony to deliver a vigorous call for continued U.S. involvement in the North African nation of Mali where the Obama administration is aiding French efforts to defeat Islamic jihadist forces.

She told the committee that the United States cannot allow Mali to become a safe haven for the group Al Qaida in the Islamic Maghreb (AQIM), warning of the risk of AQIM attacks on the United States itself.

Clinton also said she could not confirm reports that some of the terrorists involved in last week’s Algeria hostage taking were also involved in the Benghazi attack but called it a "new thread" to follow.

She did say that there is no doubt that Algerian terrorists have weapons they obtained from depots in Libya that were opened up and “liberated” after the dictator Moammar Gadhafi was toppled, with U.S. and NATO help, in 2011.

Gary Cameron / Reuters, file

Secretary of State Hillary Clinton speaks about the hostage situation in Algeria during a joint news conference with Japan's Foreign Minister Fumio Kishida (not pictured) after their meeting at the State Department in Washington Jan. 18, 2013.

Clinton said she had accepted the ARBs recommendations for improvements in security procedures and had asked her subordinates “to ensure that all 29 of them are implemented quickly and completely.” She said these changes are designed to “reduce the chances of another Benghazi happening again.”

On Thursday the Senate Foreign Relations Committee will hold its confirmation hearing for Clinton’s successor, Sen. John Kerry of Massachusetts, who is the committee’s chairman and is likely to be confirmed without any opposition.